EP0299329A2 - Process for the preparation of 2-arylthiobenzoic acids - Google Patents

Process for the preparation of 2-arylthiobenzoic acids Download PDF

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EP0299329A2
EP0299329A2 EP88110689A EP88110689A EP0299329A2 EP 0299329 A2 EP0299329 A2 EP 0299329A2 EP 88110689 A EP88110689 A EP 88110689A EP 88110689 A EP88110689 A EP 88110689A EP 0299329 A2 EP0299329 A2 EP 0299329A2
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Prior art keywords
thiophenol
formula
lithium
arylthiobenzoic
acids
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German (de)
French (fr)
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EP0299329B1 (en
EP0299329A3 (en
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Wolfgang Dr. Dipl.-Chem. Bauer
Manfred Dr. Dipl.-Chem. Langer
Kuno Dr. Dipl.-Chem. Reh
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Sanofi Aventis Deutschland GmbH
Cassella Farbwerke Mainkur AG
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Cassella AG
Cassella Farbwerke Mainkur AG
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C323/00—Thiols, sulfides, hydropolysulfides or polysulfides substituted by halogen, oxygen or nitrogen atoms, or by sulfur atoms not being part of thio groups

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  • the present invention relates to a new process for the preparation of 2-arylthiobenzoic acids of the formula I. wherein R alkyl having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms, trifluoromethyl, hydrogen, fluorine, chlorine or nitro and n denotes 1, 2, 3 or 4, where the radicals R may be the same or different, by reacting lithium 2-chlorobenzoate of the formula II with lithium thiophenolate of formula III wherein R and n have the meanings given above.
  • 2-arylthiobenzoic acids of the formula I are valuable intermediates for the preparation of thioxanthenes, which are used, for example, as photoinitiators for UV-curing lacquers (MJ Davis et al., J. Oil Col. Chem. Assoc. 61. 256 (1978)) or as starting products for powerful neuroleptics (HJ Roth and A. Kleemann, Pharmaceutical Chemistry I, Drug Synthesis, G. Thieme Verlag Stuttgart, 1982, pp. 284-286) are used.
  • sodium 2-chlorobenzoate reacts with sodium 4-chlorothiophenolate in the presence of equimolar amounts of sodium iodide at 170 ° C. (7 hours) to give 2- (4-chlorophenylthio) benzoic acid according to the procedure described in US Pat. No. 4,094,900.
  • the disadvantage of this method is the use of equimolar amounts of sodium iodide, because the high costs for sodium iodide make this process uneconomical.
  • the object of the present invention was to provide a process for the preparation of 2-arylthiobenzoic acids which does not have the economic and ecological disadvantages of the processes known from the literature.
  • the reaction is usually carried out at temperatures of 140 to 220 ° C, preferably at 170 to 200 ° C.
  • the process can be carried out either without using a solvent in the melt or in aprotic solvents at normal pressure or under pressure in an autoclave.
  • Suitable solvents are, for example: toluene, o-, m-, p-xylene, mesitylene, chlorobenzene, o-chlorotoluene, o-dichlorobenzene, tetralin, solvent naphtha, dibutyl ether, diphenyl ether, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, N, N-dimethylpropane , Dimethyl sulfoxide, dimethylaniline.
  • the process according to the invention can be carried out in an advantageous manner by using 2-chlorobenzoic acid of the formula IV and a thiophenol of formula V, where R and n have the meanings already mentioned, optionally mixed in a suitable solvent, converted with molar amounts of lithium hydroxide and / or lithium carbonate and / or lithium phosphate into the corresponding lithium salts (formula II or III) and the water of reaction at normal pressure or in vacuo Distillation removed and then heated to the desired reaction temperature.
  • the reaction is usually completed in 2 to 8 hours.
  • the resulting lithium 2-arylthio-benzoate of the formula VI taken up in water and converted into the free acid (formula I) with a mineral acid.
  • Suitable mineral acids are, for example, hydrochloric acid, sulfuric acid and phosphoric acid.
  • the aqueous phase containing the compound of the formula VI becomes the organic phase separated, whereby the organic phase can be used again for subsequent batches without further cleaning operation.
  • thiophenols of the formula V which can be used in the process according to the invention are: thiophenol, 4-fluoro-thiophenol, 3-fluoro-thiophenol, 4-chloro-thiophenol, 2-chloro-thiophenol, 2,5-dichlorothiophenol, 4-chloro 2,5-dimethyl-thiophenol, 4-methyl-thiophenol, 4-isopropyl-thiophenol, 3-trifluoromethyl-thiophenol, 4-nitro-thiophenol, 4-methoxy-thiophenol.
  • the mixture is then stirred at 185-190 ° C for 8 hours, the reaction mixture is cooled to 115 ° C and 500 ml of water are added.
  • the aqueous product phase is separated off, diluted with 1.5 l of water and adjusted to pH 2 by adding 125 g of 30% hydrochloric acid.
  • the product is ideally suited for the production of pure 2-chloro-thioxanthone by acidic cyclization.

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Abstract

2-Arylthiobenzoic acids of the formula I …<IMAGE>… in which… R denotes alkyl having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms, trifluoromethyl, hydrogen, fluorine, chlorine or nitro and… n denotes 1, 2, 3 or 4, it being possible for the radicals R to be identical or different, are prepared by reacting lithium 2-chlorobenzoate of the formula II …<IMAGE>… with lithium thiophenolate of the formula III …<IMAGE>…

Description

Gegenstand der vorliegenden Erfindung ist ein neues Verfahren zur Herstellung von 2-Arylthiobenzoesäuren der Formel I

Figure imgb0001
worin
R Alkyl mit 1 bis 4 Kohlenstoffatomen, Alkoxy mit 1 bis 4 Kohlenstoffatomen, Trifluormethyl, Wasserstoff, Fluor, Chlor oder Nitro und
n 1, 2, 3 oder 4 bedeutet, wobei die Reste R gleich oder verschieden sein können, durch Umsetzung von Lithium-2-­chlorbenzoat der Formel II
Figure imgb0002
 mit Lithium-thiophenolat der Formel III
Figure imgb0003
 worin R und n die oben angegebenen Bedeutungen haben.The present invention relates to a new process for the preparation of 2-arylthiobenzoic acids of the formula I.
Figure imgb0001
 wherein
R alkyl having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms, trifluoromethyl, hydrogen, fluorine, chlorine or nitro and
n denotes 1, 2, 3 or 4, where the radicals R may be the same or different, by reacting lithium 2-chlorobenzoate of the formula II
Figure imgb0002
 with lithium thiophenolate of formula III
Figure imgb0003
 wherein R and n have the meanings given above.

2-Arylthiobenzoesäuren der Formel I sind wertvolle Zwischenprodukte zur Herstellung von Thioxanthenen, die z.B. als Photoinitiatoren für UV-härtende Lacke (M.J. Davis et al., J. Oil Col. Chem. Assoc. 61. 256 (1978)) oder als Ausgangsprodukte für stark wirksame Neuroleptika (H.J. Roth u. A. Kleemann, Pharmazeutische Chemie I, Arzneistoffsynthese, G. Thieme Verlag Stuttgart, 1982, S. 284-286) Verwendung finden.2-arylthiobenzoic acids of the formula I are valuable intermediates for the preparation of thioxanthenes, which are used, for example, as photoinitiators for UV-curing lacquers (MJ Davis et al., J. Oil Col. Chem. Assoc. 61. 256 (1978)) or as starting products for powerful neuroleptics (HJ Roth and A. Kleemann, Pharmaceutical Chemistry I, Drug Synthesis, G. Thieme Verlag Stuttgart, 1982, pp. 284-286) are used.

Es sind bereits verschiedene Verfahren zur Herstellung von 2-Arylthiobenzoesäuren bekannt, nach denen 2-Halo­genbenzoesäuren mit Thiophenolen umgesetzt werden können.Various processes for the preparation of 2-arylthiobenzoic acids are already known, according to which 2-halobenzoic acids can be reacted with thiophenols.

Beispielsweise reagiert nach der in der US-Patentschrift 4094900 angegebenen Verfahrensweise Natrium-2-chlor­benzoat mit Natrium-4-chlorthiophenolat in Gegenwart äquimolarer Mengen Natriumjodid bei 170°C (7 Stunden) zu 2-(4-Chlorphenylthio)-benzoesäure. Der Nachteil dieser Methode liegt in der Verwendung äquimolarer Mengen Natriumjodid, denn durch die hohen Kosten für Natrium­jodid ist dieses Verfahren unwirtschaftlich. Zusätzlich tritt eine hohe Abwasserbelastung durch nicht wiederge­wonnenes Natriumjodid auf.For example, sodium 2-chlorobenzoate reacts with sodium 4-chlorothiophenolate in the presence of equimolar amounts of sodium iodide at 170 ° C. (7 hours) to give 2- (4-chlorophenylthio) benzoic acid according to the procedure described in US Pat. No. 4,094,900. The disadvantage of this method is the use of equimolar amounts of sodium iodide, because the high costs for sodium iodide make this process uneconomical. In addition, there is a high level of wastewater pollution from unrecovered sodium iodide.

Ein weiteres literaturbekanntes Verfahren ist durch die Ullmann-Reaktion von 2-Jod-benzoesäure mit Thiophenolen in Kalilauge und Gegenwart von Kupfer (J.O. Jilek et al., Collect. Czechoslov. Chem. Commun. 33, 1831 (1968), Französ. Patentschriften M. 6165, 5964) oder von 2-Chlor­benzoesäure mit Thiophenolen in Nitrobenzol in Gegenwart von Kaliumcarbonat und Kupferjodid und Kupferbronze als Katalysatoren (J.D. Brindle et al., Can. J. Chem. 61, 1869 (1983)) gegeben. Diese Reaktionen weisen als Nach­teile die Verwendung von teuren Ausgangsmaterialien wie 2-Jod-benzoesäure sowie den Einsatz von Kupfer bzw. Kupferjodid auf. Die Verwendung von Kupfer als Katalysa­tor zieht außerdem die Bildung von Nebenprodukten und damit schlechtere Ausbeuten an 2-Arylthiobenzoesäuren nach sich.Another method known from the literature is the Ullmann reaction of 2-iodo-benzoic acid with thiophenols in potassium hydroxide solution and the presence of copper (JO Jilek et al., Collect. Czechoslov. Chem. Commun. 33 , 1831 (1968), French patent specifications M 6165, 5964) or of 2-chlorobenzoic acid with thiophenols in nitrobenzene in the presence of potassium carbonate and copper iodide and copper bronze as catalysts (JD Brindle et al., Can. J. Chem. 61 , 1869 (1983)). The disadvantages of these reactions are the use of expensive starting materials such as 2-iodo-benzoic acid and the use of copper or copper iodide. The use of copper as a catalyst also leads to the formation of by-products and thus poorer yields of 2-arylthiobenzoic acids.

Der vorliegenden Erfindung lag die Aufgabe zugrunde, ein Verfahren zur Herstellung von 2-Arylthiobenzoesäuren zur Verfügung zu stellen, das die wirtschaftlichen und ökolo­gischen Nachteile der angegebenen literaturbekannten Ver­fahren nicht aufweist.The object of the present invention was to provide a process for the preparation of 2-arylthiobenzoic acids which does not have the economic and ecological disadvantages of the processes known from the literature.

Die Lösung dieser Aufgabe gelingt überraschenderweise da­durch, daß man Lithium-2-chlorbenzoat der Formel II mit Lithium-thiophenolat der Formel III zur Reaktion bringt.This object is surprisingly achieved by reacting lithium 2-chlorobenzoate of the formula II with lithium thiophenolate of the formula III.

Dabei kann auf den Einsatz von teuren Katalysatoren wie äquimolaren Mengen Natriumjodid, Kupfer, Kupferjodid oder auf den Einsatz teurer Edukte wie 2-Jod-benzoesäure ver­zichtet werden.The use of expensive catalysts such as equimolar amounts of sodium iodide, copper, copper iodide or the use of expensive starting materials such as 2-iodo-benzoic acid can be dispensed with.

Die Reaktion wird in der Regel bei Temperaturen von 140 bis 220°C, vorzugsweise bei 170 bis 200°C, ausgeführt.The reaction is usually carried out at temperatures of 140 to 220 ° C, preferably at 170 to 200 ° C.

Üblicherweise werden pro mol Thiophenolat 1 bis 1,5 mol, vorzugsweise 1,1 bis 1,3 mol, Chlorbenzoat eingesetzt.Usually 1 to 1.5 mol, preferably 1.1 to 1.3 mol, of chlorobenzoate are used per mol of thiophenolate.

Das Verfahren kann entweder ohne Verwendung eines Lösungsmittels in der Schmelze oder in aprotischen Lö­sungsmitteln bei Normaldruck oder unter Druck in einem Autoklaven durchgeführt werden.The process can be carried out either without using a solvent in the melt or in aprotic solvents at normal pressure or under pressure in an autoclave.

Geeignete Lösungsmittel sind beispielsweise: Toluol, o-, m-, p-Xylol, Mesitylen, Chlorbenzol, o-Chlortoluol, o-Dichlorbenzol, Tetralin, Solventnaphtha, Dibutylether, Diphenylether, Dimethylformamid, Dimethylacetamid, N-Methylpyrrolidon, N,N-Dimethylpropylenharnstoff, Dimethylsulfoxid, Dimethylanilin.Suitable solvents are, for example: toluene, o-, m-, p-xylene, mesitylene, chlorobenzene, o-chlorotoluene, o-dichlorobenzene, tetralin, solvent naphtha, dibutyl ether, diphenyl ether, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, N, N-dimethylpropane , Dimethyl sulfoxide, dimethylaniline.

Das erfindungsgemäße Verfahren läßt sich in vorteilhafter Weise durchführen, indem man 2-Chlorbenzoesäure der Formel IV

Figure imgb0004
und ein Thiophenol der Formel V,
Figure imgb0005
 worin R und n die bereits genannten Bedeutungen haben, gegebenenfalls in einem geeigneten Lösungsmittel mischt, mit molaren Mengen Lithiumhydroxid und/oder Lithium­carbonat und/oder Lithiumphosphat in die entsprechenden Lithiumsalze (Formel II bzw. III) überführt und das Reak­tionswasser bei Normaldruck oder im Vakuum durch Destil­lation entfernt und anschließend auf die gewünschte Reak­tionstemperatur erhitzt. Die Reaktion ist normalerweise in 2 bis 8 Stunden beendet.The process according to the invention can be carried out in an advantageous manner by using 2-chlorobenzoic acid of the formula IV
Figure imgb0004
 and a thiophenol of formula V,
Figure imgb0005
 where R and n have the meanings already mentioned, optionally mixed in a suitable solvent, converted with molar amounts of lithium hydroxide and / or lithium carbonate and / or lithium phosphate into the corresponding lithium salts (formula II or III) and the water of reaction at normal pressure or in vacuo Distillation removed and then heated to the desired reaction temperature. The reaction is usually completed in 2 to 8 hours.

Nach Vervollständigung der Reaktion wird das entstandene Lithium-2-arylthio-benzoat der Formel VI

Figure imgb0006
in Wasser aufgenommen und mit einer Mineralsäure in die freie Säure (Formel I) übergeführt. Geeignete Mineralsäuren sind zum Beispiel Salzsäure, Schwefelsäure und Phosphorsäure.After completion of the reaction, the resulting lithium 2-arylthio-benzoate of the formula VI
Figure imgb0006
 taken up in water and converted into the free acid (formula I) with a mineral acid. Suitable mineral acids are, for example, hydrochloric acid, sulfuric acid and phosphoric acid.

Bei Verwendung von mit Wasser nicht oder schwer mischba­ren Lösungsmitteln wird die wäßrige, die Verbindung der Formel VI enthaltende Phase, von der organischen Phase abgetrennt, wobei die organische Phase ohne weitere Reinigungsoperation für Folgeansätze wieder eingesetzt werden kann.When using solvents which are immiscible or difficult to mix with water, the aqueous phase containing the compound of the formula VI becomes the organic phase separated, whereby the organic phase can be used again for subsequent batches without further cleaning operation.

Setzt man aprotische, mit Wasser mischbare Lösungsmittel ein, wird dieses vor dem Wasserzusatz durch Destillation entfernt.If aprotic, water-miscible solvents are used, this is removed by distillation before the water is added.

Die in den allgemeinen Formeln I, III und V genannten Reste R können gleich oder verschieden sein. Sie können die 2-, 3-, 4- und 5-Stellung des aromatischen Ringes substituieren. Für n = 1 sind die 2-, 3- und 4-Stellungen bevorzugt. Ganz besonders bevorzugt ist die 4-Stellung.The radicals R mentioned in the general formulas I, III and V can be the same or different. You can substitute the 2-, 3-, 4- and 5-position of the aromatic ring. For n = 1, the 2, 3 and 4 positions are preferred. The 4-position is very particularly preferred.

Für n = 2 können die Substituenten R in 2,3-, 2,4-, 2,5-, 3,4-, 3,5- und 4,5-Stellung stehen. Für n = 3 sind ebenfalls alle denkbaren Kombinationen möglich,bevorzugt ist die 2,4,5-Substitution.For n = 2, the substituents R can be in the 2,3-, 2,4-, 2,5-, 3,4-, 3,5- and 4,5-position. All conceivable combinations are also possible for n = 3, the 2,4,5 substitution is preferred.

Als Thiophenole der Formel V können nach dem erfindungs­gemäßen Verfahren beispielsweise eingesetzt werden: Thiophenol, 4-Fluor-thiophenol, 3-Fluor-thiophenol, 4-Chlor-thiophenol, 2-Chlor-thiophenol, 2,5-Dichlor­thiophenol, 4-Chlor-2,5-dimethyl-thiophenol, 4-Methyl-­thiophenol, 4-Isopropyl-thiophenol, 3-Trifluormethyl-­thiophenol, 4-Nitro-thiophenol, 4-Methoxy-thiophenol.Examples of thiophenols of the formula V which can be used in the process according to the invention are: thiophenol, 4-fluoro-thiophenol, 3-fluoro-thiophenol, 4-chloro-thiophenol, 2-chloro-thiophenol, 2,5-dichlorothiophenol, 4-chloro 2,5-dimethyl-thiophenol, 4-methyl-thiophenol, 4-isopropyl-thiophenol, 3-trifluoromethyl-thiophenol, 4-nitro-thiophenol, 4-methoxy-thiophenol.

Beispiel 1example 1 2-(4-Chlorphenylthio)-benzoesäure2- (4-chlorophenylthio) benzoic acid

Eine Mischung von 144,6 g 4-Chlor-thiophenol und 172,2 g 2-Chlor-benzoesäure in 450 g Tetralin wird mit 96,4 g Lithiumhydroxid-monohydrat versetzt und am Wasserabschei­der zur Entfernung von ca. 54 ml Reaktionswasser auf 185-190°C geheizt.96.4 g of lithium hydroxide monohydrate are added to a mixture of 144.6 g of 4-chloro-thiophenol and 172.2 g of 2-chloro-benzoic acid in 450 g of tetralin, and the mixture is removed on a water separator to remove approx. 54 ml of water of reaction. Heated at 190 ° C.

Anschließend rührt man 8 Stunden bei 185-190°C nach, kühlt das Reaktionsgemisch auf 115°C und fügt 500 ml Wasser zu.The mixture is then stirred at 185-190 ° C for 8 hours, the reaction mixture is cooled to 115 ° C and 500 ml of water are added.

Die wäßrige Produktphase wird abgetrennt, mit 1,5 l Was­ser verdünnt und durch Zusatz von 125 g Salzsäure 30%ig auf pH 2 gestellt.The aqueous product phase is separated off, diluted with 1.5 l of water and adjusted to pH 2 by adding 125 g of 30% hydrochloric acid.

Die ausgefallene 2-(4-Chlorphenylthio)-benzoesäure wird durch Filtration isoliert, mit Wasser gewaschen und getrocknet.
Ausbeute: 290,2 g (95% d.Theorie, bezogen auf 4-Chlorthiophenol)
Reinheitsgrad: 96% (HPLC)
Schmelzpunkt: 230-235°CThe precipitated 2- (4-chlorophenylthio) benzoic acid is isolated by filtration, washed with water and dried.
Yield: 290.2 g (95% of theory, based on 4-chlorothiophenol)
Purity: 96% (HPLC)
Melting point: 230-235 ° C

Das Produkt eignet sich hervorragend zur Herstellung von reinem 2-Chlor-thioxanthon durch saure Cyclisierung.The product is ideally suited for the production of pure 2-chloro-thioxanthone by acidic cyclization.

VergleichsbeispieleComparative examples

Verfährt man nach den Angaben des Beispiels 1, setzt jedoch statt 96,4 g Lithiumhydroxid-monohydrat 92 g Natriumhydroxid bzw. 123 g Kaliumhydoxid ein, erhält man folgende Ergebnisse: eingesetztes Alkalihydroxid Ausbeute an I, bez. auf 4-Chlor-thiophenol (% d.Th.) Reingehalt an I der erhaltenen Rohware Schmelzp. (°C) NaOH 54 65 % 170-198 KOH 52 59 % 190-198 If the procedure of Example 1 is followed, but 92 g of sodium hydroxide or 123 g of potassium hydroxide are used instead of 96.4 g of lithium hydroxide monohydrate, the following results are obtained: Alkali hydroxide used Yield of I, on 4-chloro-thiophenol (% of theory) Pure I content of the raw material obtained Melting point (° C) NaOH 54 65% 170-198 KOH 52 59% 190-198

In der folgenden Tabelle sind weitere 2-Arylthiobenzoe­säuren aufgeführt, die nach den Angaben des Beispiels 1 durch Umsetzung von Lithium-2-chlor-benzoat mit Lithium­thiophenolaten hergestellt werden können.
In der Tabelle ist angegeben:

  • in Spalte 1: das eingesetzte Thiophenol der Formel V
  • in Spalte 2: die erhaltene 2-Arylthiobenzoesäure der Formel I
  • in Spalte 3: die Ausbeute an I, bezogen auf das eingesetzte Thiophenol
  • in Spalte 4: der Schmelzpunkt der erhaltenen 2-Arylthiobenzoesäure
2-Arylthiobenzoesäuren aus Lithium-2-chlor-benzoat und Lithium-thiophenolaten Beispiel Thiophenol (V) 2-Arylthiobenzoesäure (I) Ausbeute (% d.Th.) Schmelzpunkt (°C) 2 4-Methyl-thiophenol 2-Phenylthio-benzoesäure 85 164 - 167 3 4-Fluor-thiophenol 2-(4-Fluorphenylthio)-benzoesäure 86 172 - 170 4 4-Methylthiophenol 2-(4-Methylphenylthio-benzoesäure 89 210 - 215 5 4-Isopropyl-thio phenol 2-(4-Isopropylphenylthio)-benzoesäure 85 148 - 152 6 2-Chlor-thiophenol 2-(2-Chlorphenylthio)-benzoesäure 80 169 - 172 7 4-Methoxy-thiophenol 2-(4-Methoxyphenylthio)-benzoesäure 83 225 - 229 8 4-Chlor-2,5-dimethyl-thiophenol 2-(4-Chlor-2,5-dimethylphenylthio)-benzoesäure 84 182 - 185 9 4-Nitro-thiophenol 2-(4-Nitrophenylthio)-benzoesäure 80 221 - 225 10 3-Trifluormethylthiophenol 2-(3-Trifluormethylphenylthio)-benzoesäure 83 149 - 153 The following table lists further 2-arylthiobenzoic acids which, according to Example 1, can be prepared by reacting lithium 2-chloro-benzoate with lithium thiophenolates.
The table shows:
  • in column 1: the thiophenol of the formula V used
  • in column 2: the 2-arylthiobenzoic acid of the formula I obtained
  • in column 3: the yield of I, based on the thiophenol used
  • in column 4: the melting point of the 2-arylthiobenzoic acid obtained
2-arylthiobenzoic acids from lithium 2-chloro-benzoate and lithium thiophenolates example Thiophenol (V) 2-arylthiobenzoic acid (I) Yield (% of theory) Melting point (° C) 2nd 4-methyl-thiophenol 2-phenylthio-benzoic acid 85 164-167 3rd 4-fluoro-thiophenol 2- (4-fluorophenylthio) benzoic acid 86 172-170 4th 4-methylthiophenol 2- (4-methylphenylthio-benzoic acid 89 210-215 5 4-isopropyl-thio phenol 2- (4-isopropylphenylthio) benzoic acid 85 148-152 6 2-chloro-thiophenol 2- (2-chlorophenylthio) benzoic acid 80 169-172 7 4-methoxy-thiophenol 2- (4-methoxyphenylthio) benzoic acid 83 225-229 8th 4-chloro-2,5-dimethyl-thiophenol 2- (4-chloro-2,5-dimethylphenylthio) benzoic acid 84 182-185 9 4-nitro-thiophenol 2- (4-nitrophenylthio) benzoic acid 80 221-225 10th 3-trifluoromethylthiophenol 2- (3-trifluoromethylphenylthio) benzoic acid 83 149-153

Claims (5)

1. Verfahren zur Herstellung von 2-Arylthiobenzoesäuren der Formel I,
Figure imgb0007
 worin
R Alkyl mit 1 bis 4 Kohlenstoffatomen, Alkoxy mit 1 bis 4 Kohlenstoffatomen, Trifluormethyl, Wasserstoff, Fluor, Chlor oder Nitro und
n 1, 2, 3 oder 4 bedeutet,
      wobei die Reste R gleich oder verschieden sein können,
dadurch gekennzeichnet, daß Lithium-2-chlorbenzoat der Formel II
Figure imgb0008
 mit Lithium-thiophenolat der Formel III
Figure imgb0009
 worin R und n die oben genannten Bedeutungen haben, umgesetzt wird.1. Process for the preparation of 2-arylthiobenzoic acids of the formula I,
Figure imgb0007
 wherein
R alkyl having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms, trifluoromethyl, hydrogen, fluorine, chlorine or nitro and
n means 1, 2, 3 or 4,
where the radicals R can be the same or different,
characterized in that lithium 2-chlorobenzoate of the formula II
Figure imgb0008
 with lithium thiophenolate of formula III
Figure imgb0009
 wherein R and n have the meanings given above, is implemented. 2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß die Umsetzung bei Temperaturen von 140 bis 220°C, vorzugsweise bei 170 bis 200°C ausgeführt wird.2. The method according to claim 1, characterized in that the reaction is carried out at temperatures of 140 to 220 ° C, preferably at 170 to 200 ° C. 3. Verfahren nach Ansprüchen 1 und 2, dadurch gekenn­zeichnet, daß pro mol Lithium-thiophenolat der Formel III 1 bis 1,5 mol, vorzugsweise 1,1 bis 1,3 mol, Lithium-2-­chlorbenzoat der Formel II eingesetzt werden.3. Process according to Claims 1 and 2, characterized in that 1 to 1.5 mol, preferably 1.1 to 1.3 mol, of lithium 2-chlorobenzoate of the formula II are used per mol of lithium thiophenolate of the formula III. 4. Verfahren nach Ansprüchen 1 bis 3, dadurch gekenn­zeichnet, daß die Reaktion in einem aprotischen Lösungs­mittel ausgeführt wird.4. Process according to Claims 1 to 3, characterized in that the reaction is carried out in an aprotic solvent. 5. Verfahren nach Ansprüchen 1 bis 3, dadurch gekenn­zeichnet, daß die Reaktion lösungsmittelfrei in der Schmelze ausgeführt wird.5. Process according to claims 1 to 3, characterized in that the reaction is carried out solvent-free in the melt.
EP88110689A 1987-07-11 1988-07-05 Process for the preparation of 2-arylthiobenzoic acids Expired - Lifetime EP0299329B1 (en)

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Application Number Priority Date Filing Date Title
DE19873723079 DE3723079A1 (en) 1987-07-11 1987-07-11 METHOD FOR PRODUCING 2-ARYLTHIOBENZOESAEUR
DE3723079 1987-07-11

Publications (3)

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EP0299329A2 true EP0299329A2 (en) 1989-01-18
EP0299329A3 EP0299329A3 (en) 1991-03-13
EP0299329B1 EP0299329B1 (en) 1993-09-29

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EP88110689A Expired - Lifetime EP0299329B1 (en) 1987-07-11 1988-07-05 Process for the preparation of 2-arylthiobenzoic acids

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US (1) US4902826A (en)
EP (1) EP0299329B1 (en)
JP (1) JPS6470459A (en)
DE (2) DE3723079A1 (en)
DK (1) DK358288A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0480270A1 (en) * 1990-10-06 1992-04-15 CASSELLA Aktiengesellschaft Arylsulfides and process for their fabrication
EP0903340A1 (en) * 1994-03-17 1999-03-24 IHARA CHEMICAL INDUSTRY Co., Ltd. Process for production of alkoxycarbonylthioaryl compounds

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999018057A1 (en) * 1997-10-06 1999-04-15 Massachusetts Institute Of Technology Preparation of diaryl ether by condensation reactions
US7282590B2 (en) * 2004-02-12 2007-10-16 The Research Foundation Of State University Of New York Drug conjugates
ITTO20060575A1 (en) * 2006-08-02 2008-02-03 Univ Pisa INHIBITORS OF ZINC PROTEINASE TIOARIL SUBSTITUTED AND THEIR USES

Citations (2)

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Publication number Priority date Publication date Assignee Title
US4094900A (en) * 1977-05-19 1978-06-13 Smithkline Corporation Method of preparing aryloxybenzoic and arylthiobenzoic acids
EP0272742A1 (en) * 1986-12-12 1988-06-29 Stauffer Agricultural Chemicals Company, Inc. Method for preparation of mercaptobenzoates

Family Cites Families (1)

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Publication number Priority date Publication date Assignee Title
BE557002A (en) * 1956-07-09

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4094900A (en) * 1977-05-19 1978-06-13 Smithkline Corporation Method of preparing aryloxybenzoic and arylthiobenzoic acids
EP0272742A1 (en) * 1986-12-12 1988-06-29 Stauffer Agricultural Chemicals Company, Inc. Method for preparation of mercaptobenzoates

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
CHEMICAL ABSTRACTS Band 108, 1. - 15. Februar 1988, Seite 553, Zusammenfassung Nr. 36939a, Columbus, Ohio, US; O.G. KULINKOVICH et al.: "Reaction of alpha-bromocyclopropyl phenyl ketones with lithium thiophenolate via a concealed nucleophilic substitution mechanism at the halogen atom" & Zh. Org. Khim. 1987, Band 23, Nr. 5, Seiten 976-981 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0480270A1 (en) * 1990-10-06 1992-04-15 CASSELLA Aktiengesellschaft Arylsulfides and process for their fabrication
EP0903340A1 (en) * 1994-03-17 1999-03-24 IHARA CHEMICAL INDUSTRY Co., Ltd. Process for production of alkoxycarbonylthioaryl compounds

Also Published As

Publication number Publication date
JPS6470459A (en) 1989-03-15
EP0299329B1 (en) 1993-09-29
DE3884488D1 (en) 1993-11-04
EP0299329A3 (en) 1991-03-13
DK358288A (en) 1989-01-12
US4902826A (en) 1990-02-20
DK358288D0 (en) 1988-06-29
DE3723079A1 (en) 1989-01-19

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